Lightroom is one of the best editing programs to edit your photos. There are many features you can use to correct bad lighting or give your photos a whole new look. Lightroom has a free mobile app and a desktop app that requires a subscription that you can use on your computer. Here are 3 features in Lightroom Mobile that you can use on your photos.
HSL Sliders

Using the Lightroom Mobile App go to the color section on the bottom toolbar and in the top right is the Mix Button. Here in the image above you can see that you can adjust the Hue, Saturation, and Luminance for each color in the photo. This is a great tool to use because many times when you take a photo there can be to much blue or yellow in the image and you may want to adjust the hue or saturation of those colors to make the photo look better. You can also adjust Luminance to darken the color or lighten it adding more definition to the image. For example many times the sky can be too light, to fix that you can decrease the luminance to give it more definition to see the clouds.
Texture, Clarity, and Dehaze

The Texture, Clarity, and Dehaze sliders located in the effects section are very useful. Many times you will take a photo and it will be a little hazy or foggy and not have enough definition. Dehaze is a very good tool for removing any haze from the image. The texture slider will add more texture to the image. The Clarity Slider will add definition to the objects or subjects in the image and it will make it pop more. In the image above you can see where there is some haze in the sky, if you wanted to reduce that you can adjust the dehaze slider.
Masks

Using masks is probably one of the most important things you can use in lightroom. By using masks you are able to select certain elements of an image and you can adjust the colors and effects of just that portion of the image. Lightroom now has auto selection which will auto-select the sky for you or the subject like in the image. You can also use the brush and just paint over the section of the image you want to change. This is very useful for adjusting things like the contrast, highlights and shadows for certain elements of the image like the sky or the subject. Texture, Clarity, and Dehaze also work well with masks.
Result

Here is a before and after photo of a combination of using all of these features. The first image looks much duller and by adjusting parts of the image you change the tone of your image and bring out the colors and definition more.